Wiring Substrate Dam Design for Underfill Resin Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor devices with flip-chip bonded semiconductor elements, large-sized semiconductor elements lead to areas where underfill resin cannot fill, causing corrosion and reliability issues with the wiring pattern.
Innovation Solution
A wiring substrate design with a solder resist and dam configuration where the distance between the solder resist opening and the dam is varied, controlling the underfill resin flow to ensure precise coverage of the wiring pattern, even in areas difficult to fill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant distance is maintained between the solder resist opening and the dam, then the manufacturing process is simple, but the underfill resin cannot fill areas far from the feeding area, causing wiring pattern corrosion
Solution Approach 1:
The dam structure implements local quality by varying the distance between the solder resist opening and the dam at different locations. Specifically, the distance is set to be smaller in regions farther from the underfill resin feeding area and larger near the feeding area, creating location-specific characteristics that optimize underfill resin distribution and ensure complete coverage of the wiring pattern.
Solution Approach 2:
The dam structure transitions from a static constant-distance design to a dynamic variable-distance design. The distance between the solder resist opening and the dam is dynamically adjusted based on the position relative to the underfill resin feeding area, allowing the structure to adapt to different filling requirements at different locations.
2Reliability
If the semiconductor element size is increased, then the device performance is improved, but areas appear where underfill resin cannot reach, causing corrosion and electromigration
Solution Approach 1:
The dam structure implements local quality by varying the distance between the solder resist opening and the dam at different locations. Specifically, the distance is set to be smaller in regions farther from the underfill resin feeding area and larger near the feeding area, creating location-specific characteristics that optimize underfill resin distribution and ensure complete coverage of the wiring pattern.
3Reliability
If the dam is positioned closer to the solder resist opening in all areas, then underfill resin coverage is improved, but the dam structure becomes more complex
Solution Approach 1:
The dam structure implements local quality by varying the distance between the solder resist opening and the dam at different locations. Specifically, the distance is set to be smaller in regions farther from the underfill resin feeding area and larger near the feeding area, creating location-specific characteristics that optimize underfill resin distribution and ensure complete coverage of the wiring pattern.
Data Source
AI summary
A wiring substrate 11 includes a wiring substrate main body 31 having a semiconductor element mounting area A, a wiring pattern 33 provided on an upper surface 31A of the wiring substrate main body 31 at a portion corresponding to the semiconductor element mounting area A, a solder resist 35 provided on the upper surface 31A of the wiring substrate main body 31 and having an opening portion 43 whose size is substantially equal to the semiconductor element mounting area A when viewed from a top, and a dam 37 provided on the solder resist 35 to block an underfill resin 13 provided in a clearance between the semiconductor element 12 and the wiring substrate main body 31. A distance between an inner wall of the opening portion 43 of the solder resist 35 and an inner wall of the dam 37 is partially varied.